Not Applicable.
Not Applicable.
Tangential rolling heads have two molding rolls which are rotatably supported at the ends of lever arms. The lever arms are adapted to be pivoted about a common axis of a basic body in order to vary the spacing between the molding rolls. The basic body is provided with means for loading it into a machine tool with those means usually having a shank which laterally projects from the basic body. The workpiece is rotatingly driven during the machining operation and the molding rolls move transversely towards the workpiece and machining is completed when the molding rolls and the axis of the workpiece are in one plane. This end position is normally reached after 15 to 30 rotations of the workpiece.
If different threads and threads of different diameters are to be made it requires to exchange the molding rolls or to change the spacing of the molding rolls from each other by displacing the lever arms via suitable adjusting screws with each associated lever arm being associated with an adjusting screw.
The Fette company journal xe2x80x9cVerstellbarer Tangential-Rollkopfhalter fxc3xcr NC-und CNC-Drehautomatenxe2x80x9d has made known a rolling head holder in which a clamping bolt can be fastened in a recess of the basic body with the bolt, in turn, accommodating a spring steel sheet in a recess. The spring steel sheet is fixed in the clamping bolt by means of a clamping sleeve. The spring steel sheet is fork-shaped. outside the clamping bolt and interacts with a spindle traversing the lever arms. The spring steel sheet has the function of maintaining the adjusted axial position of the molding rolls and to yield if the relative orientation of the workpiece and the molding rolls is not central. Since a relative displacement occurs with respect to the holder if the levers carrying the molding rolls are pivoted the spring steel sheet is of a fork shape in order to compensate the different positions.
Now that the speeds of NC machines and rolling heads increase more and more high torques result during the start-up and stop, which causes the spring steel sheet to get under a significant load. Thus, ruptures occur again and again, which interrupts the production process.
The object of the invention is to provide a tangential rolling head in which the holder maintains its function even in case of a high load.
The sheet metal element is of a rigid design in the invention. Thus, it is intended not to bend at all or only in a negligible manner if the annular groove effects a relative motion with respect to the sheet metal element. Rather, disc springs are located on the two sides of the sheet metal element adjacent to the recess, which makes the sheet metal element more or less pivotable as a whole if a deflection from the central position should become necessary.
The invention not only helps in keeping the rolling head in a position central to the tool if the distance of the rolling head axis is varied, but we will also obtain a spring action for the case that the tool is not central towards the rolling head. The spring load is absorbed by the disc springs which have a long service life. A relatively small change of the angle is achieved for the spring metal sheet, thus avoiding any tilt in the spindle groove.
The tangential rolling head of the invention, as known rolling heads do as well, obtains a balance in length if the distance of the axis is varied in the rolling head.
There is no fixed connection between the rolling head and the basic body. Therefore, the rolling head may be removed from the holder in a simple way, e.g. for a roller change, settings by a gauge, etc. When the rolling head is inserted the sheet metal element will engage the spindle groove without any aid.
Another specific advantage is that the inventive holder for the tangential rolling head is built very compactly. The space which is left vacant as compared to conventional rolling heads may be utilized for fastening different types.